package org.apache.maven.project;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import java.util.HashMap;
import java.util.Map;

import org.apache.maven.model.building.ModelCache;

/**
 * A simple model cache used to accelerate model building during a reactor build.
 * 
 * @author Benjamin Bentmann
 */
class ReactorModelCache implements ModelCache {

  private final Map<CacheKey, Object> models = new HashMap<CacheKey, Object>(256);

  public Object get(String groupId, String artifactId, String version, String tag) {
    return models.get(new CacheKey(groupId, artifactId, version, tag));
  }

  public void put(String groupId, String artifactId, String version, String tag, Object data) {
    models.put(new CacheKey(groupId, artifactId, version, tag), data);
  }

  private static final class CacheKey {

    private final String groupId;

    private final String artifactId;

    private final String version;

    private final String tag;

    private final int hashCode;

    public CacheKey(String groupId, String artifactId, String version, String tag) {
      this.groupId = (groupId != null) ? groupId : "";
      this.artifactId = (artifactId != null) ? artifactId : "";
      this.version = (version != null) ? version : "";
      this.tag = (tag != null) ? tag : "";

      int hash = 17;
      hash = hash * 31 + this.groupId.hashCode();
      hash = hash * 31 + this.artifactId.hashCode();
      hash = hash * 31 + this.version.hashCode();
      hash = hash * 31 + this.tag.hashCode();
      hashCode = hash;
    }

    @Override
    public boolean equals(Object obj) {
      if (this == obj) {
        return true;
      }

      if (!(obj instanceof CacheKey)) {
        return false;
      }

      CacheKey that = (CacheKey) obj;

      return artifactId.equals(that.artifactId) && groupId.equals(that.groupId) && version.equals(that.version)
          && tag.equals(that.tag);
    }

    @Override
    public int hashCode() {
      return hashCode;
    }

  }

}
